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, the molecules in front don't get out of the way until that pressure and that energy build up in front, and it leaves a cone that we call the mock cone. and when that cone passes over your place on the ground, that's when you have a sonic boom. and that's all that built-up energy that is passing over you. >> and meanwhile, we have an asteroid about the size of a football field passing by the earth today. hakeem, how rare is that? and, you know, how lucky were we? >> well, you know, if you ask about things from space hitting earth, it's incredibly common, right? something like two tons of material from space fall to earth every day. but if you compare how frequently things occur as a function of their size, then as they get bigger, they become rarer. so if you look at events that are big enough to, say, wipe out a city, you may expect once per century to come to earth. and the latest one that we know of is an object that hit in russia in 1908, known as the tunguska event. it's common, but not as common that we should be concerned. >> the asteroid we saw today, the thing we really have t
Search Results 0 to 5 of about 6 (some duplicates have been removed)

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